The present invention relates to a method and an apparatus for producing filter rods having plug-space-plug configurations, which are segmented and attached to tobacco rods of cigarettes.
Cigarettes typically comprise a wrapped tobacco column that optionally is tipped with a filter. The filter, in turn, may optionally be a composite filter comprising a plurality of (possibly dissimilar) filter rod segments. The dissimilar filter rod segments making up the composite filter may, for example, include different base filter materials or may comprise the same base filter material, but with alternate segments being impregnated with a particulate material such as carbon particles. Alternatively, the filter may comprise spaced apart filter material segments with cavities therebetween for receiving adsorbent particles such as carbon granules, beads or capsules.
Known apparatuses for the production of composite filters suffer from the disadvantage that the plurality of filter rod segments making up the composite filter, having been assembled into the desired combined filter configuration by the combining device, may not register with filling apparatus which inserts granular, beads or capsules in the cavities.